Maturation of luteinizing hormone (gonadotropin-releasing hormone) secretion across puberty: evidence for altered regulation in obese peripubertal girls.
BACKGROUND
Peripubertal obesity (body mass index-for-age >or= 95%) in girls is associated with hyperandrogenemia. LH likely contributes to this relationship, but overnight LH secretion in obese girls is poorly characterized.


OBJECTIVE
The aim of the study was to evaluate LH pulse characteristics in obese girls throughout pubertal maturation.


METHODS
We conducted a cross-sectional analysis.


METHODS
The study was performed in a general clinical research center.


METHODS
Eight nonobese and five obese Tanner 1-2 girls participated, as well as 32 nonobese and 12 obese Tanner 3-5 girls.


METHODS
Blood samples were collected every 10 min overnight (from 1900 to 0700 h).


METHODS
LH pulse frequency, amplitude, and mean LH were measured in three 4-h time blocks (block 1, 1900-2300 h; block 2, 2300-0300 h; and block 3, 0300-0700 h).


RESULTS
Tanner stage 1-2 nonobese girls demonstrated nocturnal increases of LH frequency (P < 0.01, block 1 vs. 2) and mean LH (P < 0.05, block 1 vs. 2 and 3). Obese Tanner 1-2 girls had lower 12-h LH frequency and LH amplitude (P < 0.05 for both), with no overnight changes of LH pulse parameters. Compared to normal, LH frequency was elevated in Tanner 3-5 obese girls (P < 0.01 in all blocks), whereas LH amplitude was low (P < 0.05 in all blocks). Overnight increases of LH amplitude were observed in nonobese Tanner 3-5 girls (P < 0.0001), but not in obese Tanner 3-5 girls.


CONCLUSIONS
Obesity in prepubertal and early pubertal girls is associated with reduced LH secretion and reduced nocturnal changes of LH. In later pubertal girls, obesity is linked with reduced LH amplitude, but elevated LH frequency; the latter may reflect effects of hyperandrogenemia.
McCartney
Christopher R
CR
Division of Endocrinology and Metabolism, Department of Medicine, Box 800391, University of Virginia Health System, Charlottesville, Virginia 22908, USA. cm2hq@virginia.edu
Prendergast
Kathleen A
KA
Blank
Susan K
SK
Helm
Kristin D
KD
Chhabra
Sandhya
S
Marshall
John C
JC
D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D011627:Puberty / Q000378:metabolism*; D013739:Testosterone / Q000097:blood
D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone